Elastomeric laminates for consumer products

ABSTRACT

Elastic laminates and articles for manufacture are provided. The elastic laminate can include one or more facing layers comprising one or more thermoplastic resins and one or more propylene-based polymers, and one or more inner layers comprising one or more propylene-based polymers. Each facing layer can include at least 50% by weight of the one or more propylene-based polymers where the propylene-based polymer has (i) 60 wt % or more units derived from propylene, (ii) isotactically arranged propylene derived sequences, and (iii) a heat of fusion less than 45 J/g.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to propylene-basedpolymers for making articles, such as films and fabrics.

2. Description of the Related Art

Materials with good stretchability and elasticity are used tomanufacture a variety of disposable articles in addition to durablearticles including incontinence pads, disposable diapers, trainingpants, clothing, undergarments, sports apparel, automotive trim,weather-stripping, gaskets, and furniture upholstery. For clothing,stretchability and elasticity are performance attributes that allow thematerials to provide a closely conforming fit to the body of the wearer.Various types of elastic laminates have been used for such materials.

Elastic laminates, especially those used as diaper waist bands, legcuffs, and elastic stretch engines, have been constructed from anelastic film as an inner layer with an inelastic member as the facinglayer. The facing layer is intended to contact the wearer or user.Examples of elastic laminates include an inner layer of an elasticstyrenic block copolymer (SBC) compound laminated between facing layersof inelastic polypropylene (PP) nonwoven. The SBC layer is relativelyincompatible with the PP facing layer. As such, an adhesive tie layerresin is used to provide a good bond between the facing layer and theelastic layer. However, adhesive tie layers increase the complexity ofthe lamination process and add overall cost to the production process.

There is a need, therefore, for an elastic laminate having goodstretchability and elasticity constructed from compatible inner andfacing layers that do not require an adhesive tie layer therebetween.

SUMMARY OF THE INVENTION

Elastic laminates and articles for manufacture are provided. In at leastone specific embodiment, the elastic laminate comprises one or morefacing layers comprising one or more thermoplastic resins and one ormore propylene-based polymers, wherein the facing layers each compriseat least 50% by weight of the one or more propylene-based polymers; andone or more inner layers comprising one or more propylene-basedpolymers, wherein each propylene-based polymer has (i) 60 wt % or moreunits derived from propylene, (ii) isotactically arranged propylenederived sequences, and (iii) a heat of fusion less than 45 J/g.

In at least one other specific embodiment, the elastic laminatecomprises an inner layer at least partially disposed between two or morefacing layers, each layer comprising at least 50% by weight of one ormore propylene-based polymers having (i) 60 wt % or more units derivedfrom propylene, (ii) isotactically arranged propylene derived sequences,and (iii) a heat of fusion less than 45 J/g., wherein at least one ofthe two or more facing layers further comprises one or more onethermoplastic resins.

In at least one specific embodiment, the article for manufacturecomprises an elastic laminate having one or more facing layers disposedat least partially about one or more inner layers, wherein the facinglayers and inner layers each comprise at least 50% by weight of one ormore propylene-based polymers having (i) 60 wt % or more units derivedfrom propylene, (ii) isotactically arranged propylene derived sequences,and (iii) a heat of fusion less than 45 J/g.

DETAILED DESCRIPTION

A detailed description will now be provided. Depending on the context,all references below to the “invention” can in some cases refer tocertain specific embodiments only. In other cases it will be recognizedthat references to the “invention” will refer to subject matter recitedin one or more, but not necessarily all, of the claims.

Facing Layer

In one or more embodiments, the elastic laminate includes one or morefacing layers that are elastic or semi-elastic and one or more innerlayers. The elastic contribution of the facing layer enhances theoverall elastic performance of the laminate. Furthermore, the elastic orsemi-elastic facing layer reduces the need for a highly elastic inner,thereby offering a wider selection of inner materials.

As used herein, the terms “elastic” and “semi-elastic” refer to anymaterial having a tension set of 80% or less, or 60% or less, or 50% orless, or 25% or less, at 100% elongation at a temperature between theglass transition temperature and the crystalline melting point. Elasticpolymer materials and compositions are also referred to in the art as“elastomers” and “elastomeric.”

In one or more embodiments, the facing layer includes one or morepropylene-based polymers. In one or more embodiments, the facing layerincludes a blend of one or more propylene-based polymers and one or morethermoplastic resins. In one or more embodiments, the one or more facinglayers include at least 60 wt % of a propylene-based elastomer. The oneor more facing layers can include at least 70 wt % of a propylene-basedelastomer. The one or more facing layers can include at least 80 wt % ofa propylene-based elastomer. The one or more facing layers can includeat least 90 wt % of a propylene-based elastomer. The one or more facinglayers can include at least 95 wt % of a propylene-based elastomer.

Inner Layer

In one or more embodiments, the one or more inner layers are disposed atleast partially between the one or more facing layers. Because the oneor more facing layers are constructed from one or more elastic orsemi-elastic materials, the overall elastic performance of the elasticlaminate is enhanced and therefore, reduces the need for a highlyelastic inner layer. Preferably, the one or more inner layers includeone or more propylene-based polymers. The one or more inner layers canalso include a blend of one or more propylene-based polymers and one ormore thermoplastic resins.

Propylene-Based Polymer

The propylene-based polymer can be propylene-α-olefin copolymers,propylene-α-olefin-diene terpolymers, or propylene-diene copolymers. Forsimplicity and ease of description, however, the term “propylene-basedpolymer” as used herein refers to propylene-α-olefin copolymers,propylene-α-olefin-diene terpolymers, and propylene-diene copolymers.

The propylene-based polymer can be prepared by polymerizing propylenewith one or more comonomers. In at least one embodiment, thepropylene-based polymer can be prepared by polymerizing propylene withone or more C₂ and/or C₄-C₈ α-olefin. In at least one other specificembodiment, the propylene-based polymer can be prepared by polymerizingpropylene with one or more dienes. In at least one other specificembodiment, the propylene-based polymer can be prepared by polymerizingpropylene with ethylene and/or at least one C₄-C₂₀ α-olefin, or acombination of ethylene and/or at least one C₄-C₂₀ α-olefin and one ormore dienes. The one or more dienes can be conjugated or non-conjugated.Preferably, the one or more dienes are non-conjugated.

The comonomers can be linear or branched. Preferred linear comonomersinclude ethylene or C₄ to C₈ α-olefins, more preferably ethylene,1-butene, 1-hexene, and 1-octene, even more preferably ethylene or1-butene. Preferred branched comonomers include 4-methyl-1-pentene,3-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. In one or moreembodiments, the comonomer can include styrene.

Illustrative dienes can include but are not limited to5-ethylidene-2-norbornene (ENB); 1,4-hexadiene; 5-methylene-2-norbornene(MNB); 1,6-octadiene; 5-methyl-1,4-hexadiene;3,7-dimethyl-1,6-octadiene; 1,3-cyclopentadiene; 1,4-cyclohexadiene;vinyl norbornene (VNB); dicyclopendadiene (DCPD), and combinationsthereof. Preferably, the diene is ENB.

Preferred methods and catalysts for producing the propylene-basedpolymers are found in publications US 2004/0236042 and WO 05/049672 andin U.S. Pat. No. 6,881,800, which are all incorporated by referenceherein. Pyridine amine complexes, such as those described in WO03/040201are also useful to produce the propylene-based polymers useful herein.The catalyst can involve a fluxional complex, which undergoes periodicintra-molecular re-arrangement so as to provide the desired interruptionof stereoregularity as in U.S. Pat. No. 6,559,262. The catalyst can be astereorigid complex with mixed influence on propylene insertion, seeRieger EP1070087. The catalyst described in EP1614699 could also be usedfor the production of backbones suitable for the invention.

The propylene-based polymer can have an average propylene content on aweight percent basis of from about 60 wt % to about 99.7 wt %, morepreferably from about 60 wt % to about 99.5 wt %, more preferably fromabout 60 wt % to about 97 wt %, more preferably from about 60 wt % toabout 95 wt % based on the weight of the polymer. In one embodiment, thebalance comprises a C₂ and/or C₄-C₈ α-olefin. In another embodiment, thebalance comprises diene. In another embodiment, the balance comprisesone or more dienes and one or more of the α-olefins describedpreviously. Other preferred ranges are from about 80 wt % to about 95 wt% propylene, more preferably from about 83 wt % to about 95 wt %propylene, more preferably from about 84 wt % to about 95 wt %propylene, and more preferably from about 84 wt % to about 94 wt %propylene based on the weight of the polymer. The balance of thepropylene-based polymer comprises a diene and optionally, one or morealpha-olefins. In one or more embodiments above or elsewhere herein, thealpha-olefin is butene, hexene or octene. In other embodiments, twoalpha-olefins are present, preferably ethylene and one of butene, hexeneor octene.

Preferably, the propylene-based polymer comprises about 0.3 wt % toabout 24 wt %, of a non-conjugated diene based on the weight of thepolymer, more preferably from about 0.5 wt % to about 12 wt %, morepreferably about 0.6 wt % to about 8 wt %, and more preferably about 0.7wt % to about 5 wt %. In other embodiments, the diene content rangesfrom about 0.3 wt % to about 10 wt %, more preferably from about 0.3 toabout 5 wt %, more preferably from about 0.3 wt % to about 4 wt %,preferably from about 0.3 wt % to about 3.5 wt %, preferably from about0.3 wt % to about 3.0 wt %, and preferably from about 0.3 wt % to about2.5 wt % based on the weight of the polymer. In one or more embodimentsabove or elsewhere herein, the propylene-based polymer comprises ENB inan amount of from about 0.5 to about 4 wt %, more preferably from about0.5 to about 2.5 wt %, and more preferably from about 0.5 to about 2.0wt %.

In other embodiments, the propylene-based polymer comprises propyleneand diene in one or more of the ranges described above with the balancecomprising one or more C₂ and/or C₄-C₂₀ olefins. In general, this willamount to the propylene-based polymer preferably comprising from about 5to about 40 wt % of one or more C₂ and/or C₄-C₂₀ olefins based theweight of the polymer. When C₂ and/or a C₄-C₂₀ olefins are present thecombined amounts of these olefins in the polymer is preferably at leastabout 5 wt % and falling within the ranges described herein. Otherpreferred ranges for the one or more α-olefins include from about 5 wt %to about 35 wt %, more preferably from about 5 wt % to about 30 wt %,more preferably from about 5 wt % to about 25 wt %, more preferably fromabout 5 wt % to about 20 wt %, more preferably from about 5 to about 17wt % and more preferably from about 5 wt % to about 16 wt %.

The propylene-based polymer can have a weight average molecular weight(Mw) of about 5,000,000 or less, a number average molecular weight (Mn)of about 3,000,000 or less, a z-average molecular weight (Mz) of about10,000,000 or less, and a g′ index of 0.95 or greater measured at theweight average molecular weight (Mw) of the polymer using isotacticpolypropylene as the baseline, all of which can be determined by sizeexclusion chromatography, e.g., 3D SEC, also referred to as GPC-3D asdescribed herein.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a Mw of about 5,000 to about 5,000,000g/mole, more preferably a Mw of about 10,000 to about 1,000,000, morepreferably a Mw of about 20,000 to about 500,000, more preferably a Mwof about 50,000 to about 400,000, wherein Mw is determined as describedherein.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a Mn of about 2,500 to about 2,500,000g/mole, more preferably a Mn of about 5,000 to about 500,000, morepreferably a Mn of about 10,000 to about 250,000, more preferably a Mnof about 25,000 to about 200,000, wherein Mn is determined as describedherein.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a Mz of about 10,000 to about 7,000,000g/mole, more preferably a Mz of about 50,000 to about 1,000,000, morepreferably a Mz of about 80,000 to about 700,000, more preferably a Mzof about 100,000 to about 500,000, wherein Mz is determined as describedherein.

The molecular weight distribution index (MWD=(Mw/Mn)), sometimesreferred to as a “polydispersity index” (PDI), of the propylene-basedpolymer can be about 1.5 to 40. In an embodiment the MWD can have anupper limit of 40, or 20, or 10, or 5, or 4.5, and a lower limit of 1.5,or 1.8, or 2.0. In one or more embodiments above or elsewhere herein,the MWD of the propylene-based polymer is about 1.8 to 5 and mostpreferably about 1.8 to 3. Techniques for determining the molecularweight (Mn and Mw) and molecular weight distribution (MWD) can be foundin U.S. Pat. No. 4,540,753 (Cozewith, Ju and Verstrate) (which isincorporated by reference herein for purposes of U.S. practices) andreferences cited therein, in Macromolecules, 1988, volume 21, p 3360(Verstrate et al.), which is herein incorporated by reference forpurposes of U.S. practice, and references cited therein, and inaccordance with the procedures disclosed in U.S. Pat. No. 6,525,157,column 5, lines 1-44, which patent is hereby incorporated by referencein its entirety.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a g′ index value of 0.95 or greater,preferably at least 0.98, with at least 0.99 being more preferred,wherein g′ is measured at the Mw of the polymer using the intrinsicviscosity of isotactic polypropylene as the baseline. For use herein,the g′ index is defined as:

$g^{\prime} = \frac{\eta_{b}}{\eta_{l}}$where π_(b) is the intrinsic viscosity of the propylene-based polymerand π_(l) is the intrinsic viscosity of a linear polymer of the sameviscosity-averaged molecular weight (M_(v)) as the propylene-basedpolymer. π_(l)=KM_(v) ^(α), K and α are measured values for linearpolymers and should be obtained on the same instrument as the one usedfor the g′ index measurement.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a density of about 0.85 g/cm³ to about0.92 g/cm³, more preferably, about 0.87 g/cm³ to 0.90 g/cm³, morepreferably about 0.88 g/cm³ to about 0.89 g/cm³ at room temperature asmeasured per ASTM D-1505.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a melt flow rate (MFR, 2.16 kg weight @230° C.), equal to or greater than 0.2 g/10 min as measured according toASTM D-1238(A) as modified (described below). Preferably, the MFR (2.16kg @ 230° C.) is from about 0.5 g/10 min to about 200 g/10 min and morepreferably from about 1 g/10 min to about 100 g/10 min. In anembodiment, the propylene-based polymer has an MFR of from about 0.5g/10 min to about 200 g/10 min, especially from about 2 g/10 min toabout 30 g/10 min, more preferably from about 5 g/10 min to about 30b/10 min, more preferably from about 10 g/10 min to about 30 g/10 min ormore specially from about 10 g/10 min to about 25 g/10 min.

The propylene-based polymer can have a Mooney viscosity, ML (1+4)@ 125°C., as determined according to ASTM D1646, of less than 100, morepreferably less than 75, even more preferably less than 60, and mostpreferably less than 30.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can have a heat of fusion (Hf) determinedaccording to the DSC procedure described later, which is greater than orequal to about 0.5 Joules per gram (J/g), and is ≦about 80 J/g,preferably ≦about 75 J/g, preferably ≦about 70 J/g, more preferably≦about 60 J/g, more preferably ≦about 50 J/g, more preferably ≦about 45J/g, more preferably ≦about 35 J/g. Also preferably, the propylene-basedpolymer has a heat of fusion that is greater than or equal to about 1J/g, preferably greater than or equal to about 5 J/g. In anotherembodiment, the propylene-based polymer can have a heat of fusion (Hf),which is from about 0.5 J/g to about 75 J/g, preferably from about 1 J/gto about 75 J/g, more preferably from about 0.5 J/g to about 35 J/g.Preferred propylene-based polymers and compositions can be characterizedin terms of both their melting points (TM) and heats of fusion, whichproperties can be influenced by the presence of comonomers or stericirregularities that hinder the formation of crystallites by the polymerchains. In one or more embodiments, the heat of fusion ranges from alower limit of 1.0 J/g, or 1.5 J/g, or 3.0 J/g, or 4.0 J/g, or 6.0 J/g,or 7.0 J/g, to an upper limit of 30 J/g, or 35 J/g, or 40 J/g, or 45J/g, or 50 J/g, or 60 J/g or 70 J/g, or 75 J/g, or 80 J/g.

The crystallinity of the propylene-based polymer can also be expressedin terms of percentage of crystallinity (i.e. % crystallinity). In oneor more embodiments above or elsewhere herein, the propylene-basedpolymer has a % crystallinity of from 0.5% to 40%, preferably 1% to 30%,more preferably 5% to 25% wherein % crystallinity is determinedaccording to the DSC procedure described below. In another embodiment,the propylene-based polymer preferably has a crystallinity of less than40%, preferably about 0.25% to about 25%, more preferably from about0.5% to about 22%, and most preferably from about 0.5% to about 20%. Asdisclosed above, the thermal energy for the highest order ofpolypropylene is estimated at 189 J/g (i.e., 100% crystallinity is equalto 189 J/g.).

In addition to this level of crystallinity, the propylene-based polymerpreferably has a single broad melting transition. However, thepropylene-based polymer can show secondary melting peaks adjacent to theprincipal peak, but for purposes herein, such secondary melting peaksare considered together as a single melting point, with the highest ofthese peaks (relative to a baseline as described herein) beingconsidered the melting point of the propylene-based polymer.

The propylene-based polymer preferably has a melting point (measured byDSC) of equal to or less than 105° C., preferably less than 100° C.,preferably less than 90° C., preferably less than 80° C., morepreferably less than or equal to 75° C., preferably from about 25° C. toabout 80° C., preferably about 25° C. to about 75° C., more preferablyabout 30° C. to about 65° C.

The Differential Scanning Calorimetry (DSC) procedure can be used todetermine heat of fusion and melting temperature of the propylene-basedpolymer. The method is as follows: About 6 to 10 mg of a sheet of thepolymer pressed at approximately 200° C. to 230° C. and allowed to coolby hanging in air under ambient conditions, is removed with a punch dieand annealed at room temperature for 48 hours. At the end of thisperiod, the sample is placed in a Differential Scanning Calorimeter(Perkin Elmer Pyris 1 Thermal Analysis System) and cooled to about −50°C. to −70° C. The sample is heated at about 20° C./min to attain a finaltemperature of about 180° C. to 200° C. The term “melting point,” asused herein, is the highest peak among principal and secondary meltingpeaks as determined by DSC, discussed above. The thermal output isrecorded as the area under the melting peak of the sample, which istypically at a maximum peak at about 30° C. to about 175° C. and occursbetween the temperatures of about 0° C. and about 200° C. The thermaloutput is measured in Joules as a measure of the heat of fusion. Themelting point is recorded as the temperature of the greatest heatabsorption relative to a baseline measurement within the range ofmelting of the sample.

The propylene-based polymer can have a triad tacticity of threepropylene units, as measured by ¹³C NMR, of 75% or greater, 80% orgreater, 82% or greater, 85% or greater, or 90% or greater. Preferredranges include from about 50 to about 99%, more preferably from about 60to about 99%, more preferably from about 75 to about 99% and morepreferably from about 80 to about 99%; and in other embodiments fromabout 60 to about 97%. Triad tacticity is determined by the methodsdescribed in U.S. Patent Application Publication 20040236042.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can be a blend of discrete randompropylene-based polymers. Such blends can include ethylene-basedpolymers and propylene-based polymers, or at least one of each suchethylene-based polymers and propylene-based polymers. The number ofpropylene-based polymers can be three or less, more preferably two orless.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can include a blend of two propylene-basedpolymers differing in the olefin content, the diene content, or both.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can include a propylene based elastomericpolymer produced by random polymerization processes leading to polymershaving randomly distributed irregularities in stereoregular propylenepropagation. This is in contrast to block copolymers in whichconstituent parts of the same polymer chains are separately andsequentially polymerized.

In another embodiment, the propylene-based polymers can includecopolymers prepared according the procedures in WO 02/36651. Likewise,the propylene-based polymer can include polymers consistent with thosedescribed in WO 03/040201, WO 03/040202, WO 03/040095, WO 03/040201, WO03/040233, and/or WO 03/040442. Additionally, the propylene-basedpolymer can include polymers consistent with those described in EP 1 233191, and U.S. Pat. No. 6,525,157, along with suitable propylene homo-and copolymers described in U.S. Pat. No. 6,770,713 and U.S. PatentApplication Publication 2005/215964, all of which are incorporated byreference. The propylene-based polymer can also include one or morepolymers consistent with those described in EP 1 614 699 or EP 1 017729.

In one or more embodiments above or elsewhere herein, thepropylene-based polymer can be or include a blend of two or morepropylene-based polymers differing in MFR. For example, thepropylene-based polymer can be or include a blend having a firstpropylene-based polymer having a MFR less than about 5 g/10 min and asecond propylene-based polymer having a MFR greater than about 20 g/10min. In one or more embodiments, the blend the first propylene-basedpolymer can have a MFR less than about 10 g/10 min, or less than about15 g/10 min, or less than about 20 g/10 min and the secondpropylene-based polymer can a MFR greater than about 15 g/10 min, orgreater than about 20 g/10 min, or greater than about 30 g/10 min.

Grafted (Functionalized) Backbone

In one or more embodiments, the propylene-based polymer can be grafted(i.e. “functionalized”) using one or more grafting monomers. As usedherein, the term “grafting” denotes covalent bonding of the graftingmonomer to a polymer chain of the propylene-based polymer.

Preferably, the grafting monomer is at least one ethylenicallyunsaturated carboxylic acid or acid derivative, such as an acidanhydride, ester, salt, amide, imide, acrylates or the like.Illustrative monomers include but are not limited to acrylic acid,methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconicacid, mesaconic acid, maleic anhydride, 4-methylcyclohexene-1,2-dicarboxylic acid anhydride,bicyclo(2.2.2)octene-2,3-dicarboxylic acid anhydride,1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic acid anhydride,2-oxa-1,3-diketospiro(4.4)nonene, bicyclo(2.2.1)heptene-2,3-dicarboxylicacid anhydride, maleopimaric acid, tetrahydrophtalic anhydride,norbornene-2,3-dicarboxylic acid anhydride, nadic anhydride, methylnadic anhydride, himic anhydride, methyl himic anhydride, andx-methylbicyclo(2.2.1)heptene-2,3- dicarboxylic acid anhydride. Othersuitable grafting monomers include methyl acrylate and higher alkylacrylates, methyl methacrylate and higher alkyl methacrylates, acrylicacid, methacrylic acid, hydroxy-methyl methacrylate, hydroxyl-ethylmethacrylate and higher hydroxy-alkyl methacrylates and glycidylmethacrylate. Maleic anhydride is a preferred grafting monomer.

In one or more embodiments, the grafted propylene based polymer includesfrom about 0.5 to about 10 wt % ethylenically unsaturated carboxylicacid or acid derivative, more preferably from about 0.5 to about 6 wt %,more preferably from about 0.5 to about 3 wt %; in other embodimentsfrom about 1 to about 6 wt %, more preferably from about 1 to about 3 wt%. In a preferred embodiment wherein the graft monomer is maleicanhydride, the maleic anhydride concentration in the grafted polymer ispreferably in the range of about 0.1 to about 6 wt. %, preferably atleast about 0.5 wt. % and highly preferably about 1.5 wt. %.

Styrene and derivatives thereof such as paramethyl styrene, or otherhigher alkyl substituted styrenes such as t-butyl styrene can be used asa charge transfer agent in presence of the grafting monomer to inhibitchain scission. This allows further minimization of the beta scissionreaction and the production of a higher molecular weight graftedpolymer.

Preparing Grafted Propylene-Based Polymers

The grafted propylene-based polymer can be prepared using conventionaltechniques. For example, the graft polymer can be prepared in solution,in a fluidized bed reactor, or by melt grafting. A preferred graftedpolymer can be prepared by melt blending in a shear-imparting reactor,such as an extruder reactor. Single screw but preferably twin screwextruder reactors such as co-rotating intermeshing extruders orcounter-rotating non-intermeshing extruders but also co-kneaders such asthose sold by Buss are especially preferred.

In one or more embodiments, the grafted polymer can be prepared by meltblending the ungrafted propylene-based polymer with a free radicalgenerating catalyst, such as a peroxide initiator, in the presence ofthe grafting monomer. The preferred sequence for the grafting reactionincludes melting the propylene-based polymer, adding and dispersing thegrafting monomer, introducing the peroxide, and venting the unreactedmonomer and by-products resulting from decomposition of the peroxide.Other sequences can include feeding the monomers and the peroxidepre-dissolved in a solvent.

Illustrative peroxide initiators include but are not limited to: diacylperoxides such as benzoyl peroxide; peroxyesters such as tert-butylperoxy benzoate, tert-butylperoxy acetate,00-tert-butyl-0-(2-ethylhexyl)monoperoxy carbonate; peroxyketals such asn-butyl-4,4-di-(tert-butyl peroxy) valerate; and dialkyl peroxides suchas 1,1-bis(tertbutylperoxy) cyclohexane,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,2,2-bis(tert-butylperoxy)butane, dicumylperoxide,tert-butylcumylperoxide, Di-(2-tert-butylperoxy-isopropyl-(2))benzene,di-tert-butylperoxide (DTBP),2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane,2,5-dimethyl-2,5-di(tert-butylperoxy)- hexyne, 3,3,5,7,7-pentamethyl1,2,4-trioxepane; and the like.

Thermoplastic Resins

In one or more embodiments, the thermoplastic resin includes an olefinicthermoplastic resin. The “olefinic thermoplastic resin” can be anymaterial that is not a “rubber” and that is a polymer or polymer blendconsidered by persons skilled in the art as being thermoplastic innature, e.g., a polymer that softens when exposed to heat and returns toits original condition when cooled to room temperature. The olefinicthermoplastic resin can contain one or more polyolefins, includingpolyolefin homopolymers and polyolefin copolymers. Except as statedotherwise, the term “copolymer” means a polymer derived from two or moremonomers (including terpolymers, tetrapolymers, etc.), and the term“polymer” refers to any carbon-containing compound having repeat unitsfrom one or more different monomers.

Illustrative polyolefins can be prepared from mono-olefin monomersincluding, but are not limited to, monomers having 2 to 7 carbon atoms,such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene,1-octene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene,mixtures thereof and copolymers thereof with (meth)acrylates and/orvinyl acetates. Preferably, the olefinic thermoplastic resin isunvulcanized or non cross-linked.

In one or more embodiments, the olefinic thermoplastic resin containspolypropylene. The term “polypropylene” as used herein broadly means anypolymer that is considered a “polypropylene” by persons skilled in theart (as reflected in at least one patent or publication), and includeshomo, impact, and random polymers of propylene. Preferably, thepolypropylene used in the compositions described herein has a meltingpoint above 110° C., includes at least 90 wt % propylene units, andcontains isotactic sequences of those units. The polypropylene can alsoinclude atactic sequences or syndiotactic sequences, or both. Thepolypropylene can either derive exclusively from propylene monomers(i.e., having only propylene units) or derive from mainly propylene(more than 80% propylene) with the remainder derived from olefins,particularly ethylene, and/or C₄-C₁₀ alpha-olefins. The polypropylenecan have a high MFR (e.g., from a low of 10, or 15, or 20 g/10 min to ahigh of 25 to 30 g/10 min. The polypropylene can also have a lower MFR,e.g., “fractional” polypropylenes which have an MFR less than 1.0. Thosewith high MFR are preferred for ease of processing or compounding.

In one or more embodiments, the olefinic thermoplastic resin is orincludes isotactic polypropylene. Preferably, the olefinic thermoplasticresin contains one or more crystalline propylene homopolymers orcopolymers of propylene having a melting temperature of from 110° C. to170° C. or higher as measured by DSC. Preferred copolymers of propyleneinclude, but are not limited to, terpolymers of propylene, impactcopolymers of propylene, random polypropylene and mixtures thereof.Preferred comonomers have 2 carbon atoms, or from 4 to 12 carbon atoms.Preferably, the comonomer is ethylene. Such olefinic thermoplasticresins and methods for making the same are described in U.S. Pat. No.6,342,565.

The term “random polypropylene” as used herein broadly means a singlephase copolymer of propylene having up to 9 wt %, preferably from 2 wt %to 8 wt % of an alpha olefin comonomer. Preferred alpha olefincomonomers have 2 carbon atoms, or from 4 to 12 carbon atoms.Preferably, the alpha olefin comonomer is ethylene.

Blending and Additives

In one or more embodiments, the one or more propylene-based polymers andone or more thermoplastic resins can be blended by melt-mixing to form ablend that contains no processing oil. In other words, the blend isprocessed in the absence of processing oil. Examples of machinerycapable of generating the shear and mixing include extruders withkneaders or mixing elements with one or more mixing tips or flights,extruders with one or more screws, extruders of co or counter rotatingtype, Banbury mixer, Farrell Continuous mixer, and the Buss Kneader. Thetype and intensity of mixing, temperature, and residence time requiredcan be achieved by the choice of one of the above machines incombination with the selection of kneading or mixing elements, screwdesign, and screw speed (generally <3000 RPM).

In one or more embodiments, the blend can include the propylene-basedpolymer in an amount ranging from a low of about 60, 70 or 75 wt % to ahigh of about 80, 90, 95 wt %. In one or more embodiments, the blend caninclude the one or more polyolefinic thermoplastic components in anamount ranging from a low of about 5, 10 or 20 wt % to a high of about25, 30, or 40 wt %.

When the one or more thermoplastic resins are present, the blend caninclude about 60 wt % to about 95 wt % of the propylene-based polymerand about 5 wt % to about 40 wt % of the one or more thermoplasticresins. In one or more embodiments, the blend can include about 70 wt %to about 95 wt % of the propylene-based polymer and about 5 wt % toabout 30 wt % of the one or more thermoplastic resins. In one or moreembodiments, the blend can include about 65 wt % to about 80 wt % of thepropylene-based polymer and about 20 wt % to about 35 wt % of the one ormore thermoplastic resins.

In one or more embodiments, the blend can contain one or more additives,which can be introduced at the same time as the other components, orlater downstream in case of using an extruder or Buss kneader, or onlylater in time. Examples of such additives are antioxidants, antiblockingagents, antistatic agents, ultraviolet stabilizers, foaming agents, andprocessing aids. Such additives can comprise from about 0.1 to about 10percent by weight based on the total weight of blend. The additives canbe added to the blend in pure form or in master batches.

Fibers

In one or more embodiments, any one of the one or more facing layers andthe one or more inner layers can be a multicomponent layer. The term“multicomponent”, as used herein, refers to fibers which have beenformed from at least two polymers extruded from separate extruders andmeltblown or spun together to form one fiber. Multicomponent fibers arealso referred to in the art as bicomponent fibers. The polymers used inmulticomponent fibers are typically different from each other; however,conjugated fibers can be monocomponent fibers. The polymers can bearranged in distinct zones across the cross-section of the conjugatedfibers and extend continuously along the length of the conjugatedfibers. The configuration of conjugated fibers can be, for example, asheath/inner arrangement wherein one polymer is surrounded by another, aside by side arrangement, a pie arrangement or an “islands-in-the-sea”arrangement. Conjugated fibers are described in U.S. Pat. Nos.5,108,820; 5,336,552; and 5,382,400; the entire disclosures of which arehereby incorporated herein by reference. In a particular embodiment, thefibers can be part of a conjugated configuration.

In one or more embodiments, the fibers can be in the form of continuousfilament yarn, partially oriented yarn, and staple fibers. Continuousfilament yarns typically range from 40 denier to 20,000 denier(denier=number of grams per 9000 yards). Filaments currently range from1 to 20 or more denier per filament (dpf). Spinning speeds are typically800 m/min to 1500 m/min (2500 ft/min to 5000 ft/min).

Partially oriented yarn (POY) is the fiber produced directly from fiberspinning without solid state drawing, as in the continuous filament. Theorientation of the molecules in the fiber is done in the melt state justafter the molten polymer leaves the spinneret.

Staple fiber filaments can range, for example, from 1.5 dpf to 70 dpf ormore, depending on the application. There are two basic staple fiberfabrication processes: traditional and compact spinning. The traditionalprocess typically involves two steps: 1) producing, applying, finishing,and winding, followed by 2) drawing, a secondary finish application,crimping, and cutting into staple fibers.

Fabrics

Nonwoven fabrics can be made from extruded fibers that have been wovenor bonded. The extrusion process to form the extruded fibers can be Faccompanied by mechanical or aerodynamic drawing of the fibers. Theelastic fabrics described herein can be manufactured by conventionalequipment using any technique known in the art. Such methods andequipment are well known. For example, spunbond nonwoven fabrics can beproduced by spunbond nonwoven production lines produced by ReifenhauserGmbH & Co., Troisdorf, Germany. The Reifenhauser system utilizes a slotdrawing technique as described in U.S. Pat. No. 4,820,142.

The term “nonwoven” as used herein refers to a web or fabric having astructure of individual fibers or threads that are randomly interlaid,but not in any identifiable manner as is the case for a knitted fabric.The elastic fiber can be employed to prepare inventive nonwoven elasticfabrics as well as composite structures comprising the elastic nonwovenfabric in combination with nonelastic materials.

As used herein, the term “thermal bonding” refers to the heating offibers to effect the melting (or softening) and fusing of fibers suchthat a nonwoven fabric is produced. Thermal bonding includes calendarbonding and through-air bonding, as well as other methods known in theart.

The inventive nonwovens described herein include melt blown fabrics andspunbonded fabrics. Melt blown fabrics are generally webs of finefilaments having a fiber diameter in the range of from 0.1 to 20microns. Typical fiber diameters for melt blown fabrics are in the rangeof from 1 to 10 microns, or from 1 to 5 microns. The nonwoven websformed by these fine fiber diameters have very small pore sizes and can,therefore, have excellent barrier properties.

For example, in the melt blown process, the extruder melts the polymerand delivers the molten polymer to a metering melt pump. The melt pumpdelivers the molten polymer at a steady output rate to a special meltblowing die. As the molten polymer exits the die, the polymer iscontacted by high temperature, high velocity air (called process orprimary air). This air attenuates the polymer melt stream into smallfibers that are collected on a forming belt. The fibers are cooledduring transport to the belt by ambient air. Auxiliary cooling in theform of a secondary process air at low temperature or water spray can beapplied. As such, the fabric formed on the forming belt consistsessentially of randomly oriented short fibers.

Spunbond fibers are generally produced, for example, by the extrusion ofmolten polymer from either a large spinneret having typicallyapproximately 1000 holes per meter length, or with banks of smallerspinnerets, with each spinneret section containing as few as 40 holes.After exiting the spinneret, the molten fibers are quenched by across-flow air quench system, then pulled away from the spinneret andattenuated (drawn) by high speed air. Filaments formed in this mannerare collected on a screen (“wire”) or porous forming belt to form theweb. The web is then passed through compaction rolls and then betweenheated calendar rolls where the raised lands on one roll bond the web atpoints covering generally from about 10% to about 40% of its area toform a nonwoven fabric. The top calendar roll may have an embossedpattern while the bottom roll is smooth.

In some embodiments, the fabrics can be further processed. For example,the fabric can be subjected to a surface treatment process, such assizing. Thus, in some embodiments, the fabric can contain sizingadditives such as rosins, resins, or waxes. As another example, thefabric can be subjected to a tentering process. In one or moreembodiments above, blocking agents can be added to the fabric in aprocessing step subsequent to the formation of the fabric.

Films

Films can be manufactured by conventional tubular extrusion (blownbubble process) or by cast extrusion. In the cast extrusion process, themolten resin is extruded from an elongate die to the form of a web. Theweb is cast onto a chill roller, which solidifies the polymer, andfinally the web is wound into a roll. The process described above canalso include a set of embossing rolls to chill and form the film.

Films can be made with a coextruded soft or thermoplastic layer adheredto one or both sides of the inventive film. The layers are adhered by aprocess of coextrusion of the film with the layer. In these coextrudedfilms the individual layers are different in composition and retaintheir composition except at the interface layer. These layers can beeither a soft material such as an ethylene-propylene copolymer elastomerwhich is intended to reduce the adhesive sticky feel of the inventivefilm, or a thermoplastic. In one embodiment, the thermoplastic layer isused as a mechanical support for the elastic film to prevent sag. Inanother embodiment, the thermoplastic layer is used as a barrier toadhesion of the polymer film to other surfaces. In another embodiment,the thermoplastic layer becomes a part of the integral use of theelastic film in that the composite film is stretched beyond the yieldpoint of the thermoplastic layer (typically>50% elongation) and allowedto retract due to the elastic forces of the elastic inner film. In thisoperation thermoplastic film is wrinkled to lead to a desirable surfacefinish of the composite elastic film. In a particular aspect of thisembodiment, the thermoplastic is selected from polypropylene andpolyethylene.

The mechanical properties referred to above can be enhanced bymechanical orientation of the polymer film. Mechanical orientation canbe done by the temporary, forced extension of the polymer film along oneor more axis for a short period of time before it is allowed to relax inthe absence of the extensional forces. It is believed that themechanical orientation of the polymer leads to reorientation of thecrystallizable portions of the blend of the first and the secondpolymer.

Articles

The elastic laminate can be used for a variety of articles includingconsumer and industrial goods. Illustrative consumer articles and goodsinclude but are not limited to incontinence pads, disposable diapers,training pants, clothing, undergarments, sports apparel, face masks,gowns, and filtration media.

Definitions and Test Methods

For purposes of convenience, various definitions and specific testprocedures are identified below. However, when a person of ordinaryskill reads this patent and wishes to determine whether a composition orpolymer has a particular property identified in a claim, then anypublished or well-recognized method or test procedure can be followed todetermine that property, although the specifically identified procedureis preferred. Each claim should be construed to cover the results of anyof such procedures, even to the extent different procedures may yielddifferent results or measurements. Thus, a person of ordinary skill inthe art is to expect experimental variations in measured properties thatare reflected in the claims. All numerical values can be considered tobe “about” or “approximately” the stated value, in view of the nature oftesting in general.

Comonomer content: The comonomer content and sequence distribution ofthe polymers can be measured using ¹³C nuclear magnetic resonance (NMR)by methods well known to those skilled in the art. Comonomer content ofdiscrete molecular weight ranges can be measured using methods wellknown to those skilled in the art, including Fourier Transform InfraredSpectroscopy (FTIR) in conjunction with samples by GPC, as described inWheeler and Willis, Applied Spectroscopy, 1993, vol. 47, pp. 1128-1130.

In the particular case of propylene-ethylene copolymers containinggreater than 75 wt % propylene, the comonomer content can be measured asfollows. A thin homogeneous film is pressed at a temperature of about150° C. or greater, and mounted on a Perkin Elmer PE 1760 infraredspectrophotometer. A full spectrum of the sample from 600 cm⁻¹ to 4000cm⁻¹ is recorded and the monomer weight percent of ethylene can becalculated according to the following equation: Ethylene wt%=82.585−111.987X+30.045X², where X is the ratio of the peak height at1155 cm⁻¹ and peak height at either 722 cm⁻¹ or 732 cm⁻¹, whichever ishigher.

Polyene content: The amount of polyene present in a polymer can beinferred by the quantitative measure of the amount of the pendant freeolefin present in the polymer after polymerization. Several proceduressuch as iodine number and the determination of the olefin content by H¹or ¹³C nuclear magnetic resonance (NMR) have been established. Inembodiments described herein where the polyene is ENB, the amount ofpolyene present in the polymer can be measured using ASTM D3900.

Isotactic: The term “isotactic” is defined herein as a polymer sequencein which greater than 50% of the pairs of pendant methyl groups locatedon adjacent propylene units, which are inserted into the chain in aregio regular 1,2 fashion and are not part of the backbone structure,are located either above or below the atoms in the backbone chain, whensuch atoms in the backbone chain are all in one plane. Certaincombinations of polymers in blends or polymer sequences within a singlepolymer are described as having “substantially the same tacticity,”which herein means that the two polymers are both isotactic according tothe definition above.

Tacticity: The term “tacticity” refers to the stereoregularity of theorientation of the methyl residues from propylene in a polymer. Pairs ofmethyl residues from contiguous propylene units identically insertedwhich have the same orientation with respect to the polymer backbone aretermed “meso” (m). Those of opposite configuration are termed “racemic”(r). When three adjacent propylene groups have methyl groups with thesame orientation, the tacticity of the triad is ‘mm’. If two adjacentmonomers in a three monomer sequence have the same orientation, and thatorientation is different from the relative configuration of the thirdunit, the tacticity of the triad is ‘mr’. When the middle monomer unithas an opposite configuration from either neighbor, the triad has ‘rr’tacticity. The fraction of each type of triad in the polymer can bedetermined and when multiplied by 100 indicates the percentage of thattype found in the polymer.

The triad tacticity of the polymers described herein can be determinedfrom a ¹³C nuclear magnetic resonance (NMR) spectrum of the polymer asdescribed below and as described in U.S. Pat. No. 5,504,172, thedisclosure of which is hereby incorporated herein by reference.

Tacticity Index: The tacticity index, expressed herein as “m/r”, isdetermined by ¹³C nuclear magnetic resonance (NMR). The tacticity indexm/r is calculated as defined in H. N. Cheng, Macromolecules, 17, 1950(1984). An m/r ratio of 1.0 generally describes a syndiotactic polymer,and an m/r ratio of 2.0 generally describes an atactic material. Anisotactic material theoretically can have a ratio approaching infinity,and many by-product atactic polymers have sufficient isotactic contentto result in ratios of greater than 50.

Melting point and heat of fusion: The melting point (TM) and heat offusion of the polymers described herein can be determined byDifferential Scanning Calorimetry (DSC), using the ASTM E-794-95procedure. About 6 to 10 mg of a sheet of the polymer pressed atapproximately 200° C. to 230° C. and allowed to cool by hanging in airunder ambient conditions, is removed with a punch die and annealed atroom temperature for 48 hours. At the end of this period, the sample isplaced in a Differential Scanning Calorimeter (Perkin Elmer Pyris 1Thermal Analysis System) and cooled to about −50° C. to −70° C. Thesample is heated at about 20° C./min to attain a final temperature ofabout 180° C. to 200° C. The term “melting point,” as used herein, isthe highest peak among principal and secondary melting peaks asdetermined by DSC, discussed above. The thermal output is recorded asthe area under the melting peak of the sample, which is typically at amaximum peak at about 30° C. to about 175° C. and occurs between thetemperatures of about 0° C. and about 200° C. The thermal output ismeasured in Joules as a measure of the heat of fusion. The melting pointis recorded as the temperature of the greatest heat absorption relativeto a baseline measurement within the range of melting of the sample.

Molecular weight and molecular weight distribution: The molecular weightand molecular weight distribution of the polymers described herein canbe measured as follows. Molecular weight distribution (MWD) is a measureof the range of molecular weights within a given polymer sample. It iswell known that the breadth of the MWD can be characterized by theratios of various molecular weight averages, such as the ratio of theweight average molecular weight to the number average molecular weight,Mw/Mn, or the ratio of the Z-average molecular weight to the weightaverage molecular weight, Mz/Mw.

Mz, Mw, and Mn can be measured using gel permeation chromatography(GPC), also known as size exclusion chromatography (SEC). This techniqueutilizes an instrument containing columns packed with porous beads, anelution solvent, and detector in order to separate polymer molecules ofdifferent sizes. In a typical measurement, the GPC instrument used is aWaters chromatograph equipped with ultrastyro gel columns operated at145° C. The elution solvent used is trichlorobenzene. The columns arecalibrated using sixteen polystyrene standards of precisely knownmolecular weights. A correlation of polystyrene retention volumeobtained from the standards, to the retention volume of the polymertested yields the polymer molecular weight.

Average molecular weights M can be computed from the expression:

$M = \frac{\sum\limits_{i}{N_{i}M_{i}^{n + 1}}}{\sum\limits_{i}{N_{i}M_{i}^{n}}}$where Ni is the number of molecules having a molecular weight Mi. Whenn=0, M is the number average molecular weight Mn. When n=1, M is theweight average molecular weight Mw. When n=2, M is the Z-averagemolecular weight Mz. The desired MWD function (e.g., Mw/Mn or Mz/Mw) isthe ratio of the corresponding M values. Measurement of M and MWD iswell known in the art and is discussed in more detail in, for example,Slade, P. E. Ed., Polymer Molecular Weights Part II, Marcel Dekker,Inc., NY, (1975) 287-368; Rodriguez, F., Principles of Polymer Systems3^(rd) ed., Hemisphere Pub. Corp., NY, (1989) 155-160; U.S. Pat. No.4,540,753; Verstrate et al., Macromolecules, vol. 21, (1988) 3360; andreferences cited therein.

Mooney viscosity: Mooney viscosity, as used herein, is measured asML(1+4) @ 125° C. according to ASTM D1646.

Melt flow rate and melt index: The determination of the Melt Flow rate(MFR) and the Melt Index of the polymer is according to ASTM D1238 usingmodification 1 with a load of 2.16 kg. In this version of the method aportion of the sample extruded during the test was collected andweighed. The sample analysis is conducted at 230° C. with a 1 minutepreheat on the sample to provide a steady temperature for the durationof the experiment. This data is expressed as dg of sample extruded perminute. In an alternative procedure, the test is conducted in anidentical fashion except at a temperature of 190 C. This data isreferred to as MI@190 C.

Isotacticity Index: The isotacticity index is calculated according tothe procedure described in EP 0374695A2. The IR spectra of a thin filmof the material is recorded and the absorbance at 997 cm⁻¹ and theabsorbance at 973 cm-1 are determined. The quotient of the absorbance at997 cm⁻¹ to the absorbance at 973 cm⁻¹ is multiplied by 100 to yield theisotacticity index. In the determination of the absorbance at these twopositions the position of zero absorbance is the absorbance when thereis no analytical sample present in the sample beam.

EXAMPLES

The foregoing discussion can be further described with reference to thefollowing non-limiting examples. Two elastic laminates (Examples 1 and2) according to the present invention and three comparative examples(Comp. Ex. 1-3) are provided. Examples 1 and 2 had an elastic innerlayer (“layer B”) disposed between spunbond elastic facing layers(“layer A”). Comparative examples 1 and 2 were monolithic fabrics of thefacing layer alone. Comparative example 3 was a laminate having a highlyelastic SBC inner layer. As shown in Table 1 below, Examples 1 and 2having the elastic inner layer showed significantly improved elasticitycompared to non-laminates of the facing layer alone (comparativeexamples 1 and 2). Also, Examples 1 and 2 exhibited elastic propertiessimilar to that of the highly elastic SBC comparative example 3.

Examples 1 and 2

Examples 1 and 2 were A/B/A laminate structures. Each facing layer(“layer A”) is a spunbond nonwoven comprising a propylene-based polymerhaving a MFR of 80. Polymer 1 or P1 has 60 wt % or more units derivedfrom propylene, isotactically arranged propylene derived sequences, adensity of 0.868 g/cm³, and heat of fusion of about 25 J/g. Polymer 2 orP2 has 60 wt % or more units derived from propylene, isotacticallyarranged propylene derived sequences, a density of 0.865 g/cm³, and aheat of fusion of about 21 J/g. Polymer 2 had a permanent set of 15%after 100% extension, compared to 20% at 100% extension for Polymer 1,based on 65 gsm nonwoven. As such, Polymer 2 showed a higher elasticitycompared to Polymer 1.

The facing layer was made in a slot die spunmelt process to a basisweight of 50 gsm. A commercial slot die available from Reifenhauser(Reicofil ®system) was used to make the spunbond fabric. The nonwovensin Layer A were produced in a 1 m wide Reicofil 3 system, at athroughput of around 0.5 grams/hole/min.

The inner layer (“layer B”) was a cast elastic film constructed using apropylene-based polymer (“Polymer 3” or “P3”) having 60 wt % or moreunits derived from propylene, isotactically arranged propylene derivedsequences, a MFR of 3, a density of 0.860 g/cm³, and heat of fusion ofabout 10 J/g. Prior to cast film extrusion, the Polymer 3 resin wasblended with an antiblock masterbatch at an 80/20 blend ratio of thePolymer 3 resin to masterbatch to eliminate roll blocking. The antiblockmasterbatch contained 65 wt % of a propylene-based polymer (“Polymer 4”or “P4”) having 60 wt % or more units derived from propylene,isotactically arranged propylene derived sequences, a MFR of 21, densityof 0.861 g/cm³, and a heat of fusion of about 16 J/g.; 5 wt % Erucamide;and 30 wt % ABT 2500 (Talc). Polymer 3 and the antiblock masterbatchwere tumble blended and converted to cast film with a thickness of 2mils in a Black Clawson® cast film machine.

Comparative Examples

Comparative examples 1 and 2 (“Comp. Ex. 1” and “Comp. Ex. 2”) were eacha spunbond monolithic fabric at a basis weight of 100 gsm. Theproperties of the monolithic fabrics are shown as the root mean square(RMS) values calculated as ((MD²+TD²)/2)^(0.5).

Comparative example 3 was a polypropylene (PP) nonwoven facing layerthat enclosed a styrenic block copolymer (SBC) elastic film. Thepermanent set after 150% extension was measured as 6.2%. The permanentset at 100%, both As-Is and Prestretch as reported in Table 1, areestimated based on the permanent set after 150% extension.

Lamination & Testing

In Examples 1 and 2, the layers A and B were laminated using standardequipment without the use of any adhesives. The laminates were cut to adimension of 4 inches in length and 1 inch in width and tested undertension by cycling to a strain level of 100%. The first stretch cycle isdenoted as testing under “as is” condition. The samples were cycled asecond time with no hold to a strain level of 100%. This condition wasdenoted as testing under “pre stretch” condition.

From the load-displacement curve, for both the “as is” and “pre stretch”conditions, the following properties were calculated and summarized inTable 1 below.

Permanent Set (%): Strain level corresponding to zero force on return.

Load Loss (%): (Load on Ascending Curve—Load on Descending Curve/(Loadon Ascending calculated at the 50% strain level).

Hysteresis (lb-in/in): Area enclosed by the ascending and descendingportion of the load displacement curve.

Mechanical Hysteresis (lb-in/in): Area under the ascending portion ofthe load displacement curve.

Hysteresis (%): Hysteresis/Mechanical Hysteresis

PS: Pre stretch to 100% strain.

TABLE 1 Properties of Composite Laminates Comp Comp Comp EX. 1 EX. 2 Ex.1 Ex. 2 Ex. 3 Layer A: P2 P1 P2 P1 PP Layer B: P3 and P3 and N/A N/A SBCP4 P4 Layer A: P2 P1 PP Adhesive layer(s) No No No No Yes 100% As IsPermanent Set (%) 12.3 19.9 17.1 23.5 est. 6% Load Loss @ 50% 62.5 84.385.6 90.9 Strain (%) Hysteresis (lb-in/in) 0.48 1.61 1.03 1.03Mechanical Hysteresis 54 69.7 (%) 100% Pre Stretch Permanent Set (%) 9.415.6 13.9 19.2 est. 26% Load Loss @ 50% 45.1 71 67.0 77.1 Strain (%)Hysteresis (lb-in/in) 0.29 1.04 0.29 0.25 Mechanical Hysteresis 38 58.3(%)

As shown in Table 1, the permanent set values of the composite laminatesare lower than the corresponding monolithic fabrics (1 vs CE 1 and 2 vsCE 2), both in the “as is” and the “pre stretch” conditions. Moreparticularly, the addition of the elastic inner layer in Examples 1 and2 significantly improved the elasticity of the Polymer 1 or Polymer 2monolithic facing layers, as manifested in reduction of set, load lossand hysteresis. Moreover, the addition of the elastic inner layer inExamples 1 and 2 provided elasticity performance approaching that of ahighly elastic SBC laminate which is represented by Comparative Example3 (“Comp. Ex. 3”). Surprisingly, Examples 1 and 2 showed significantlyimproved elasticity without the need for additional adhesives.

Embodiments of the present invention further include:

-   1. An elastic laminate, comprising:    -   one or more facing layers comprising one or more thermoplastic        resins and one or more propylene-based polymers, wherein the        facing layers each comprise at least 50% by weight of the one or        more propylene-based polymers; and    -   one or more inner layers comprising one or more propylene-based        polymers,    -   wherein each propylene-based polymer has (i) 60 wt % or more        units derived from propylene, (ii) isotactically arranged        propylene derived sequences, and (iii) a heat of fusion less        than 45 J/g.-   2. The elastic laminate of paragraph 1, wherein the one or more    facing layers each comprise at least 80% by weight of the one or    more propylene-based polymers.-   3. The elastic laminate of paragraphs 1 or 2, wherein the one or    more inner layers each comprise at least 1% by weight of the one or    more propylene-based polymers.-   4. The elastic laminate of any of paragraphs 1 to 3, wherein the one    or more inner layers each comprise at least 50% by weight of the one    or more propylene-based polymers.-   5. The elastic laminate of any of paragraphs 1 to 4, wherein the one    or more inner layers each comprise at least 80% by weight of the one    or more propylene-based polymers.-   6. The elastic laminate of any of paragraphs 1 to 5, wherein the one    or more inner layers each comprise at least 99% by weight of the one    or more propylene-based polymers.-   7. The elastic laminate of any of paragraphs 1 to 6, wherein the one    or more facing layers are spunbond and laminated at least partially    about the one or more inner layers to form the elastic laminate.-   8. An article of manufacture, comprising:    -   an elastic laminate having one or more facing layers disposed at        least partially about one or more inner layers, wherein the        facing layers and inner layers each comprise at least 50% by        weight of one or more propylene-based polymers having (i) 60 wt        % or more units derived from propylene, (ii) isotactically        arranged propylene derived sequences, and (iii) a heat of fusion        less than 45 J/g.-   9. The article of paragraph 8, wherein the one or more facing layers    each comprise at least 80% by weight of the one or more    propylene-based polymers.-   10. The article of paragraphs 8 or 9, wherein the one or more inner    layers each comprise at least at least 1% by weight of the one or    more propylene-based polymers.-   11. The article of any of paragraphs 8 to 10, wherein the one or    more inner layers each comprise at least 50% by weight of the one or    more propylene-based polymers.-   12. The article of any of paragraphs 8 to 11, wherein the one or    more inner layers each comprise at least 80% by weight of the one or    more propylene-based polymers.-   13. The article of any of paragraphs 8 to 12, wherein the one or    more inner layers each comprise at least 99% by weight of the one or    more propylene-based polymers.-   14. The article of any of paragraphs 8 to 13, wherein the one or    more facing layers are spunbond and laminated at least partially    about the one or more inner layers to form the elastic laminate.-   15. A disposable article comprising the elastic laminate of any of    paragraphs 1 to 14.-   16. A durable article comprising the elastic laminate of any of    paragraphs 1 to 15.-   17. An elastic laminate, comprising:    -   an inner layer at least partially disposed between two or more        facing layers, each layer comprising at least 50% by weight of        one or more propylene-based polymers having (i) 60 wt % or more        units derived from propylene, (ii) isotactically arranged        propylene derived sequences, and (iii) a heat of fusion less        than 45 J/g., wherein at least one of the two or more facing        layers further comprises one or more one or more thermoplastic        resins.-   18. The elastic laminate of paragraph 17, wherein the facing layers    each comprise at least 80% by weight of the one or more    propylene-based polymers.-   19. The elastic laminate of paragraphs 17 or 18, wherein the inner    layer comprises at least two of the one or more propylene-based    polymers.-   20. The elastic laminate of any of paragraphs 17 to 19, wherein the    inner layer comprises at least 70% by weight of a first    propylene-based polymer having a MFR less than about 5 dg/min. and    at least 10% by weight of a second propylene-based polymer having a    MFR greater than about 20 dg/min.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges from any lower limit to any upper limit arecontemplated unless otherwise indicated. Certain lower limits, upperlimits and ranges appear in one or more claims below. All numericalvalues are “about” or “approximately” the indicated value, and take intoaccount experimental error and variations that would be expected by aperson having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention can be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. An elastic laminate, comprising: one or more nonwoven fabric facing layers comprising one or more thermoplastic resins and at least 80% by weight of one or more propylene-based polymers; and one or more film inner layers comprising at least 50% by weight of one or more propylene-based polymers, wherein each propylene-based polymer has (i) 60 wt % or more units derived from propylene, (ii) isotactically arranged propylene derived sequences, and (iii) a heat of fusion less than 45 J/g.
 2. The elastic laminate of claim 1, wherein the one or more inner layers each comprise at least 80% by weight of the one or more propylene-based polymers.
 3. The elastic laminate of claim 1, wherein the one or more inner layers each comprise at least 99% by weight of the one or more propylene-based polymers.
 4. The elastic laminate of claim 1, wherein the one or more facing layers are spunbond and laminated at least partially about the one or more inner layers to form the elastic laminate.
 5. An article of manufacture, comprising: an elastic laminate having one or more nonwoven fabric facing layers disposed at least partially about one or more film inner layers, wherein the facing layers and inner layers each comprise at least 50% by weight of one or more propylene-based polymers having (i) 60 wt% or more units derived from propylene, (ii) isotactically arranged propylene derived sequences, and (iii) a heat of fusion less than 45 J/g, and wherein the one or more propylene-based polymers of the one or more inner layers have an MFR from about 2 to about 30 dg/min.
 6. The article of claim 5, wherein the one or more facing layers each comprise at least 80% by weight of the one or more propylene-based polymers.
 7. The article of claim 5, wherein the one or more inner layers each comprise at least at least 1% by weight of the one or more propylene-based polymers.
 8. The article of claim 5, wherein the one or more inner layers each comprise at least 50% by weight of the one or more propylene-based polymers.
 9. The article of claim 5, wherein the one or more inner layers each comprise at least 80% by weight of the one or more propylene-based polymers.
 10. The article of claim 5, wherein the one or more inner layers each comprise at least 99% by weight of the one or more propylene-based polymers.
 11. The article of claim 5, wherein the one or more facing layers are spunbond and laminated at least partially about the one or more inner layers to form the elastic laminate.
 12. A disposable article comprising the elastic laminate of claim
 1. 13. A durable article comprising the elastic laminate of claim
 1. 14. An elastic laminate, comprising: a film inner layer at least partially disposed between two or more nonwoven fabric facing layers, each layer comprising at least 50% by weight of one or more propylene-based polymers having (i) 60 wt% or more units derived from propylene, (ii) isotactically arranged propylene derived sequences, and (iii) a heat of fusion less than 45 J/g, wherein at least one of the two or more facing layers further comprises one or more one or more thermoplastic resins, and wherein the one or more propylene-based polymers of the inner layer have an MFR from about 2 to about 30 dg/min.
 15. The elastic laminate of claim 14, wherein the facing layers each comprise at least 80% by weight of the one or more propylene-based polymers.
 16. The elastic laminate of claim 14, wherein the inner layer comprises at least two of the one or more propylene-based polymers.
 17. The elastic laminate of claim 16, wherein the inner layer comprises at least 70% by weight of a first propylene-based polymer having an MFR from about 2 to about 5 dg/min and at least 10% by weight of a second propylene-based polymer having an MFR from about 20 to about 30 dg/min.
 18. The elastic laminate of claim 1, wherein the film consists essentially of a propylene-based polymer having an MFR of from 0.5 to 30 g/ 10 min and an antiblocking agent.
 19. The elastic laminate of claim 5, wherein the film consists essentially of a propylene-based polymer having an MFR of from 0.5 to 30 g/ 10 min and an antiblocking agent.
 20. The elastic laminate of claim 14, wherein the film consists essentially of a propylene-based polymer having an MFR of from 0.5 to 30 g/ 10 min and an antiblocking agent. 